The United States has reciprocal agreements with countries outside the Waiver Program, such as Israel, that allow Americans to enter without a visa. Even within the Waiver Agreement, most countries require visas for foreigners who plan on working, attending school for credit, or permanently relocating. Some Waiver Agreement participants, such as Australia, require even tourists to obtain visas. Travel.State.gov has an interactive map that outlines the entry requirements for every country.